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THE International Atomic Energy Agency (IAEA) has recorded 2734 incidents of illegally trafficked nuclear materials since 1995. Questions including What is the material? Where were the materials sourced? and Why is the material being trafficked? need to be answered in order to close trafficking routes and stop these materials falling into the wrong hands. To do this, the material is analysed by a suite of analytical techniques in order to form a characteristic nuclear forensic fingerprint. This can then be compared to a nuclear forensic database containing representative samples of known origin to find a match. One of the key limitations of these databases is within mine heterogeneity. Representative sample databases only contain few and often small physical samples which are assumed to accurately represent a large geographical area. An increasing number of studies have determined significant within mine variation in signatures, this in some cases is larger than the variation between two different sites. This study aims to test the heterogeneity of a set of nuclear forensic signatures within vein type uranium deposits at a selection of different geographical scales. Sample sets from South West England and the Berias region of Portugal are analysed to deduce if small database samples are actually representative of large mining areas. It is also tested if these signatures are modified by the first stage of the uranium processing route; acid leaching. The nuclear forensic tools focussed on in this study are uranium and gangue mineralogy, major and minor elemental analysis, REE patterns and uranium isotope ratios. In summary, significant heterogeneity was found at all geographical scales tested. This indicates that databases need to be regularly updated as a deposit is extracted, and should include a moving average and range in signatures per site rather than a single physical sample. Although significant heterogeneity was found, in most cases, by using a selection of signatures, individual mines could be separated. It was concluded that much of the within mine variation observed in the ore sampled could be transferred through acid leaching during processing. In most cases elemental impurity patterns were not significantly effected by acid leaching, but uranium isotope signatures were variably affected and could not be traced back to their parent ore.

Signicant uncertainty is known to be present in the internal radiation dose assessments for intakes of uranium compounds. The aim of this thesis was to investigate the sources of the uncertainty in the dose assessment and in particular the biokinetic models used to describe the movement of uranium in the body. A variety of numerical and statistical approaches have been used to explore the uncertainty in the dose assessments. In particular Bayesian techniques have been applied to historical uranium in urine measurements to derive best estimates for important biokinetic parameters. Posterior probability distributions for the important lung solubility parameters have been calculated from six historical exposure cases. It was shown that improved estimates of these parameters can be obtained by sharing the information in each of the cases in the Bayesian calculation. Using these estimates, the uncertainty in the radiation doses from occupational intakes of uranium have been quantifed. Lastly, a novel Bayesian approach to identifying intakes of uranium from bioassay measurements has been developed and tested. This Bayesian approach provides a number of advantages as it incorporates the uncertainty in the bioassay measurements, intake parameters and the bioassay model parameters in a coherent way.

After the massive tsunami on 11 March 2011, the explosions at 4 reactors of the Fukushima Daiichi (I) Nuclear Power Stations (Fukushima I NPSs) in Japan led to a large radioactive cloud being ejected into the atmosphere. Radionuclides released to the atmosphere were washed out in rain causing an area of remarkably high deposition in the area to the northwest of the Fukushima I NPSs. Activity remaining in the atmosphere was dispersed further to other areas of Japan. At various times during the accident, plumes of contamination were transported from Japan to the Pacific Ocean, the North American continent, crossing the Atlantic Ocean to Europe, and eventually to Asia. Due to the lack of measurements in three major ecosystem compartments i.e. air, soil and surface water, information on the highest impact early-phase after fallout and the interpretation of long-term impacts is limited and unclear. The transfer of contaminated radionuclides to soil and air around the Fukushima I NPSs was studied using ratios of various radioisotopes to the long-lived nuclide 137Cs. It was found that ratios of three radionuclides i.e. 134,136Cs and 132Te were consistent with direction and distance in air and soil while the ratio 131I/137Cs was not. It was shown that, deposited 131I/137Cs had an inverse correlation with 137Cs activity in soil. These nuclides were key in forming the high-gamma dose rates in the early phase, particularly the high gamma energy of 132I from the 132Te/132I decay. The derived ratios of these key radionuclides in soil were used together with available measured gamma dose rates in the early phase (< 30 days) to develop a model to reconstruct and predict external gamma dose rate. Model “blind” tests showed that more than 95% of predictions were within a factor of two of measurements from 15 sites to the north, northwest and west of the power station. It is demonstrated that generic isotope ratios provide a sound basis for reconstruction of early-phase external dose rates in these most contaminated areas. For contamination in surface runoff water, lake water and fish, a previous model developed following the Chernobyl accident (AQUASCOPE) was applied to the Fukushima situation. It was shown that by adjusting for the stronger absorption of radiocaesium in soils in Japan (compared with European countries) the model could be used successfully to predict long-term contamination in aquatic systems affected by Fukushima fall out. The results of the model showed good agreement with measured data, in particular in the long-term period (around 0.5-2 years) after the accident.

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This thesis describes the development of biosensing systems incorporating eukaryotic cells. The ultimate objective of this work was to design devices capable of rapidly assessing the toxicity of effluents and environmental pollutants. Although much work remains to be done in order to achieve this goal, the work reported here demonstrates, in principle, the approaches adopted. The first approach exploited the reducing nature of healthy biological cells. So called 'redox mediated whole cell biosensors' have been described before. In this work, an algal toxicity test of short duration was developed and sensors incorporating cultured fish cells were described for the first time. The sensitivity of biosensors incorporating the green alga Selenastrum capricornutum, to diuron and pentachlorophenol, was found to compare favourably with that from other standard ecotoxicological tests. However, although the sensitivity of biosensors incorporating immobilised BF-2 fish cells was found to compare well with that of other fish cell-based toxicity tests, it appeared that whole organism tests were much more sensitive to the compounlds tested. The second approach involved the genetic manipulation of fish cells in order to incorporate luminescent reporter genes. Although this work is less well advanced, it demonstrates that the luc reporter gene can be successfully inserted into BF -2 fish cells and that these transformed cells can produce a luminescent response when incubated with luciferin substrate. Preliminary investigations have indicated that the sensitivity of luc-transformed BF-2 cells to 4-chlorophenol is comparable to that of some standard whole organism ecotoxicological tests and although much work is still required to validate this approach, it could eventually provide a simple, sensitive and rapid route to toxicity assessment.

Ship collision accidents are rare events but pose huge threat to human lives, assets, and the environment. Collision resistance of ships is usually assessed in terms of ship structural response such as member displacement, energy dissipation and the extent of damage. Many researchers have sought for effective models that compute ship stochastic response during collisions by considering the variability of collision scenario parameters. However, the models were limited by the capability of the collision computational models and did not completely capture collision scenario, and material and geometric uncertainties. In addition, the simplified models capturing the input-response relationships of the ship structural impact mechanics are in implicit forms which makes them unsuitable for assessing the performance of structural design specifications in collisions. Furthermore, with increasing ship passages in the Arctic region, the probabilities of ship-iceberg interactions are increasing, highlighting the need to focus on risk based ship designs. In this research, a conceptual stochastic modelling framework is developed for performance characterisation and quantitative risk assessment of ship-ship and ship-iceberg collisions. In this direction, an interface for automated stochastic finite element computations was developed to model ship structural resistance in reference collision scenarios. The stochastic structural response was characterised based on the onset of the ship structural failure. The focus was initially on ship-ship collisions to quantify the uncertainties experimentally and to characterise the performance for a variety of striking ships. The framework was then extended to consider probabilistic performance measures in ship-iceberg collisions. The computationally intensive collision response models were captured with efficient surrogate representations so that the performance measures can be obtained with gradient based reliability approaches. The most probable input design sets for the response distribution were sampled with Latin Hypercube models. The probabilistic performance measures were also combined with available collision frequency models from literature for risk computations and to demonstrate the risk tolerance measures. The framework underlines the significance of different risk components, providing valuable guidance for improving risk-based ship designs. Although, a double-hull crude oil carrier is presented as the struck ship, the approach can be readily extended to characterise the performance and risk of other ship structures in collisions.

Current trends in participative democracy suggest that the use of stakeholder involvement in decision making will increase in the next decade and beyond. The evolution towards stakeholder involvement is driven mainly by stakeholders’ expectation to participate in decision making on issues that affect them. The current view of international radiation protection organisations is that the stakeholders have a right to participate in decision making, but the changes to the current system of radiation protection decision making will only occur slowly through build up of positive experiences and appreciation of benefits provided by stakeholder involvement.The benefits of stakeholder involvement have already been observed in decision making in issues ranging from new nuclear build to dealing with radiological emergencies, but unsuccessful stakeholder involvement programmes have also been observed. In order to integrate stakeholder involvement further into radiation protection decision making it is important to incorporate and implement lessons learnt from both successful and unsuccessful stakeholder programmes, and understand when stakeholder involvement can be applied. My research into clearance of low radioactivity materials shows that stakeholder involvement can be applied in planned exposure situations as defined by the International Commission on Radiological Protection (ICRP). Involvement of stakeholders in planned exposure situation decision making should, however, be limited to issues with high level of reputation risk or wide ranging impacts of multiple stakeholder groups.To assess whether stakeholder involvement can be applied in the other exposure situations defined by the ICRP as emergency and existing exposure situations, the other part of my research focused on radiological emergencies. The research demonstrated that stakeholder aided decision making already has a place in solving cooperative problems of emergency management, but there is still further scope to apply stakeholder involvement in coordination of emergency management. The research shows that there is scope to integrate stakeholder involvement further into radiation protection decision making, but this must be done in a planned and organised manner.

Calls for examining the interrelations between individual and collective processes of remembering have been repeatedly made within the field of memory studies. With the tendency being to focus on either the individual or the collective level, there have been few studies that have undertaken this task in an empirically informed manner. This thesis seeks to engage in such an examination by undertaking a multi-level study of the remembrance of the Bhopal gas disaster of 1984. The gas leak in Bhopal (India) was one of the world s worst industrial disasters and has seen a long-running political contestation involving state institutions, social movement organisations (SMOs) and individual survivors. Employing an ethnographic methodology, incorporating interviews, participant observation and archival research, the study seeks to examine similarities and divergences in how these institutional, group-level and individual actors have remembered the disaster. It identifies the factors that modulated these remembrances and focuses on examining the nature of their interrelationship. The study conceptualises remembering as memory-work : an active process of meaning-making in relation to the past. The memory-work of state institutions was examined within the judicial and commemorative domains. The analysis demonstrates how state institutions engaged in a limiting of the meaning of the disaster removing from view the transnational causality of the event and the issue of corporate liability. It tracks how the survivors suffering was dehistoricised and contained within the framework of a localized claims bureaucracy. The examination of SMO memory-work focused on the activities of the two most prominent groups working in Bhopal. The analysis reveals how both organisations emphasise the continuing suffering of the survivors to challenge the state s settlement of the event. However, clear differences are outlined between the two groups in the wider frameworks of meaning employed by them to explain the suffering, assign responsibility and define justice. Memory-work at the individual level was accessed in the memory narratives of individual survivors generated through ethnographic interviews. The study examined how individual survivors have made sense of the lived experience of suffering caused by the disaster and its aftermath. The analysis revealed how the frameworks of meaning imposed by the state are deeply incommensurate with the survivors needs to express the multi-dimensionality of their suffering; it tracks how the state imposed identities are resisted but cannot be entirely overcome in individual remembrance. Engagement with the activities of the SMOs is demonstrated as enabling the development of an alternative activist remembrance for a limited group of survivors. Overall, the thesis seeks to provide a complex and empirically grounded account of the relations between the inner, individual level processes of memory linked to lived experience and the wider, historically inflected, collective and institutional registers of remembrance. The examination of the encounters between these diverse individual and collective remembrances in the context of an on-going political contestation allows the study to contribute to ongoing discussions within the field about memory politics in a global age and memory and justice.

A holistic arms control (HAC) analytical framework was employed to explore the full range of mechanisms that could potentially be utilised to effectively regulate the development, stockpiling, transfer or use of riot control agents (RCAs), incapacitants and related means of delivery. From this analysis it is clear that the Chemical Weapons Convention (CWC) and its attendant regime are the most appropriate and probably the most receptive mechanisms, at least in the short term, for the discussion of these concerns and the development of appropriate policy responses. However, the response of CWC States Parties to these issues is by no means certain and parallel processes should be established to explore alternative regulatory mechanisms with the Biological and Toxin Weapons Convention, UN drugs conventions, international and regional human rights instruments, international humanitarian law, and transfer controls potentially yielding positive results in the next five to ten year period. Other regimes that may well prove important in the longer term include: the international criminal court and other international criminal law entities; the UN Secretary General's investigation mechanism and other ad hoc UN investigatory mechanisms. A comprehensive HAC strategy for the regulation of RCAs, incapacitants and related means of delivery will also require active involvement of informed and activist civil society in societal verification; development and promotion of norms prohibiting the involvement of scientific and medical communities in weaponisation programmes intended for malign application; and far greater active engagement of such expert communities in relevant State and international policy development processes.